Decoration of Silver Nanoparticles on Porous Polymelamine as An Active Substrate for SERS Measurement and Sensing Membrane for Raman Optical Probe Application

• Main Authors: Chien-Yu Chen, 陳建宇
• Other Authors: Jyisy Yang
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/74725211273358943222

碩士 === 國立中興大學 === 化學系所 === 104 === To increase the sensitivity in detection of analyte in aqueous solution, a new method was proposed to prepare multi-dimensional substrates for surface-enhanced Raman scattering (SERS) measurements. Multi-dimensional SERS substrates were fabricated by chemically decorating of silver nanoparticles (AgNPs) on porous polymelamine, which exhibits frame-like structure. To successfully decorate AgNPs, agarose was further employed to alter the surface property of the polymelamine. Meanwhile, a seed-mediated method was employed to improve the decoration of AgNPs on the surface of the frame structure of polymelamine. To successfully produce such SERS substrates, several parameters were studies, including concentration of agarose in surface treatment, the concentration of silver nitrate in the agarose solution for formation of Ag seeds, the concentration of silver nitrate in growth of AgNPs, and the reaction time. The SERS performances of the prepared substrates were examined by probing with para-hydroxylthiophenol (pHTP). Also, the morphologies of the formed SERS substrates were examined by scanning electron microscope (SEM). The results indicated that agarose layer and Ag seed play critical roles to grow proper AgNPs for SERS measurements. With the optimal preparation condition, an enhancement factor larger than 106 can be obtained easily. To combine the advantages of the simplify of fiber-optic. in chemical sensing and the ability of SERS in spectral analysis, a series of fiber-optic sensors with different sensing geometry was constructed and characterized their sensing abilities for SERS detection. AgNPs were chemically decorated on polymelamine to form SERS substrate. Also, quartz optical fiber with a diameter of 550 μm was shaped by HF to form different geometry. By inserting optical fiber into the prepared SERS substrate, a sensitive SERS probe could be constructed, which is at least 10 times more sensitive than reported SERS probe. Both influences of the condition in preparation of SERS substrate and the geometry of optical fibers were systematically examined and optimized condition, the detection of adenine in aqueous solution reached a detection limit of 5 μM. The linear range was up to 50 μM. Practical application of the prepare SERS probe showed that adenine could be detected accurately in urine samples with a recovery ranged between 93.9% and 110.0%.